On-chip deposition of carbon nanotubes using CMOS microhotplates

Abstract

The direct deposition of carbon nanotubes on CMOS microhotplates is demonstrated inthis paper. Tungsten microhotplates, fabricated on thin SOI membranes aside CMOScontrol circuitry, are used to locally grow carbon nanotubes by chemical vapourdeposition. Unlike bulk heating of the entire chip, which could cause degradation toCMOS devices and interconnects due to high growth temperatures in excess of500 °C, this novel technique allows carbon nanotubes to be grown on-chip in localized regions.The microfabricated heaters are thermally isolated from the rest of the CMOS chip as theyare on the membranes. This allows carbon nanotubes to be grown alongside CMOScircuitry on the same wafer without any external heating, thus enabling new applications(e.g. smart gas sensing) where the integration of CMOS and carbon nanotubes isrequired.